<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>css常用值</title>
    <style>
        h1 {
            color: red;
            color: rgb(255, 0, 0);
            color: rgb(0, 255, 255);
            color: rgb(0, 255, 0);
            color: rgb(255, 0, 255);
            color: rgb(0, 0, 255);
            color: rgb(255, 255, 0);
            color: #FFFFFF;
            color: #FFF;
            color: #000000;
            color: #000;
            /*    带不透明度的颜色 1表示完全不透明 0表示完全透明 0.X(小数)半透明*/
            color: rgba(255,0,0,1);
            color: rgba(255,0,0,0.8);
            color: rgba(255,0,0,0.6);
            color: rgba(255,0,0,0.4);
            color: rgba(255,0,0,0.2);
            color: rgba(255,0,0,0);
        }
        .d1{
            width: 50px;
            height: 100px;
            background-image: url(img/mr.png);
            background-size: 50px 100px;
            background-color: cyan;
        }
        .d2{
            width: 500px;
            height: 500px;
            border: 5px solid red;
            background-image:url("img/mr.png");
            /*  设置不允许重复 */
            background-repeat: no-repeat;

            background-position: 50px 50px;
            background-position: center center;
            background-position: 50% ;

        }
        .d3{
            width: 500px;
            height: 300px;
            background-image: linear-gradient(270deg,red,blue);
        }
    </style>
</head>
<body>
<h1>测试颜色</h1>
<div class="d1"></div>
<div class="d3"></div>
<div class="d2"></div>
</body>
</html>